man/systemd.netdev.xml

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   8
   9 <refentry id="systemd.netdev" conditional='ENABLE_NETWORKD'>
  10
  11   <refentryinfo>
  12     <title>systemd.network</title>
  13     <productname>systemd</productname>
  14   </refentryinfo>
  15
  16   <refmeta>
  17     <refentrytitle>systemd.netdev</refentrytitle>
  18     <manvolnum>5</manvolnum>
  19   </refmeta>
  20
  21   <refnamediv>
  22     <refname>systemd.netdev</refname>
  23     <refpurpose>Virtual Network Device configuration</refpurpose>
  24   </refnamediv>
  25
  26   <refsynopsisdiv>
  27     <para><filename><replaceable>netdev</replaceable>.netdev</filename></para>
  28   </refsynopsisdiv>
  29
  30   <refsect1>
  31     <title>Description</title>
  32
  33     <para>Network setup is performed by
  34     <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
  35     </para>
  36
  37     <para>The main Virtual Network Device file must have the extension <filename>.netdev</filename>;
  38     other extensions are ignored. Virtual network devices are created as soon as networkd is
  39     started. If a netdev with the specified name already exists, networkd will use that as-is rather
  40     than create its own. Note that the settings of the pre-existing netdev will not be changed by
  41     networkd.</para>
  42
  43     <para>The <filename>.netdev</filename> files are read from the files located in the system
  44     network directory <filename>/usr/lib/systemd/network</filename>, the volatile runtime network
  45     directory <filename>/run/systemd/network</filename> and the local administration network
  46     directory <filename>/etc/systemd/network</filename>. All configuration files are collectively
  47     sorted and processed in lexical order, regardless of the directories in which they live.
  48     However, files with identical filenames replace each other. Files in <filename>/etc</filename>
  49     have the highest priority, files in <filename>/run</filename> take precedence over files with
  50     the same name in <filename>/usr/lib</filename>. This can be used to override a system-supplied
  51     configuration file with a local file if needed. As a special case, an empty file (file size 0)
  52     or symlink with the same name pointing to <filename>/dev/null</filename> disables the
  53     configuration file entirely (it is "masked").</para>
  54
  55     <para>Along with the netdev file <filename>foo.netdev</filename>, a "drop-in" directory
  56     <filename>foo.netdev.d/</filename> may exist. All files with the suffix <literal>.conf</literal>
  57     from this directory will be parsed after the file itself is parsed. This is useful to alter or
  58     add configuration settings, without having to modify the main configuration file. Each drop-in
  59     file must have appropriate section headers.</para>
  60
  61     <para>In addition to <filename>/etc/systemd/network</filename>, drop-in <literal>.d</literal>
  62     directories can be placed in <filename>/usr/lib/systemd/network</filename> or
  63     <filename>/run/systemd/network</filename> directories. Drop-in files in
  64     <filename>/etc</filename> take precedence over those in <filename>/run</filename> which in turn
  65     take precedence over those in <filename>/usr/lib</filename>. Drop-in files under any of these
  66     directories take precedence over the main netdev file wherever located. (Of course, since
  67     <filename>/run</filename> is temporary and <filename>/usr/lib</filename> is for vendors, it is
  68     unlikely drop-ins should be used in either of those places.)</para>
  69   </refsect1>
  70
  71   <refsect1>
  72     <title>Supported netdev kinds</title>
  73
  74     <para>The following kinds of virtual network devices may be
  75     configured in <filename>.netdev</filename> files:</para>
  76
  77     <table>
  78       <title>Supported kinds of virtual network devices</title>
  79
  80       <tgroup cols='2'>
  81         <colspec colname='kind' />
  82         <colspec colname='explanation' />
  83         <thead><row>
  84           <entry>Kind</entry>
  85           <entry>Description</entry>
  86         </row></thead>
  87         <tbody>
  88           <row><entry><varname>bond</varname></entry>
  89           <entry>A bond device is an aggregation of all its slave devices. See <ulink url="https://www.kernel.org/doc/Documentation/networking/bonding.txt">Linux Ethernet Bonding Driver HOWTO</ulink> for details.Local configuration</entry></row>
  90
  91           <row><entry><varname>bridge</varname></entry>
  92           <entry>A bridge device is a software switch, and each of its slave devices and the bridge itself are ports of the switch.</entry></row>
  93
  94           <row><entry><varname>dummy</varname></entry>
  95           <entry>A dummy device drops all packets sent to it.</entry></row>
  96
  97           <row><entry><varname>gre</varname></entry>
  98           <entry>A Level 3 GRE tunnel over IPv4. See <ulink url="https://tools.ietf.org/html/rfc2784">RFC 2784</ulink> for details.</entry></row>
  99
 100           <row><entry><varname>gretap</varname></entry>
 101           <entry>A Level 2 GRE tunnel over IPv4.</entry></row>
 102
 103           <row><entry><varname>erspan</varname></entry>
 104           <entry>ERSPAN mirrors traffic on one or more source ports and delivers the mirrored traffic to one or more destination ports on another switch.
 105           The traffic is encapsulated in generic routing encapsulation (GRE) and is therefore routable across a layer 3 network between the source switch
 106           and the destination switch.</entry></row>
 107
 108           <row><entry><varname>ip6gre</varname></entry>
 109           <entry>A Level 3 GRE tunnel over IPv6.</entry></row>
 110
 111           <row><entry><varname>ip6tnl</varname></entry>
 112           <entry>An IPv4 or IPv6 tunnel over IPv6</entry></row>
 113
 114           <row><entry><varname>ip6gretap</varname></entry>
 115           <entry>A Level 2 GRE tunnel over IPv6.</entry></row>
 116
 117           <row><entry><varname>ipip</varname></entry>
 118           <entry>An IPv4 over IPv4 tunnel.</entry></row>
 119
 120           <row><entry><varname>ipvlan</varname></entry>
 121           <entry>An ipvlan device is a stacked device which receives packets from its underlying device based on IP address filtering.</entry></row>
 122
 123           <row><entry><varname>macvlan</varname></entry>
 124           <entry>A macvlan device is a stacked device which receives packets from its underlying device based on MAC address filtering.</entry></row>
 125
 126           <row><entry><varname>macvtap</varname></entry>
 127           <entry>A macvtap device is a stacked device which receives packets from its underlying device based on MAC address filtering.</entry></row>
 128
 129           <row><entry><varname>sit</varname></entry>
 130           <entry>An IPv6 over IPv4 tunnel.</entry></row>
 131
 132           <row><entry><varname>tap</varname></entry>
 133           <entry>A persistent Level 2 tunnel between a network device and a device node.</entry></row>
 134
 135           <row><entry><varname>tun</varname></entry>
 136           <entry>A persistent Level 3 tunnel between a network device and a device node.</entry></row>
 137
 138           <row><entry><varname>veth</varname></entry>
 139           <entry>An Ethernet tunnel between a pair of network devices.</entry></row>
 140
 141           <row><entry><varname>vlan</varname></entry>
 142           <entry>A VLAN is a stacked device which receives packets from its underlying device based on VLAN tagging. See <ulink url="http://www.ieee802.org/1/pages/802.1Q.html">IEEE 802.1Q</ulink> for details.</entry></row>
 143
 144           <row><entry><varname>vti</varname></entry>
 145           <entry>An IPv4 over IPSec tunnel.</entry></row>
 146
 147           <row><entry><varname>vti6</varname></entry>
 148           <entry>An IPv6 over IPSec tunnel.</entry></row>
 149
 150           <row><entry><varname>vxlan</varname></entry>
 151           <entry>A virtual extensible LAN (vxlan), for connecting Cloud computing deployments.</entry></row>
 152
 153           <row><entry><varname>geneve</varname></entry>
 154           <entry>A GEneric NEtwork Virtualization Encapsulation (GENEVE) netdev driver.</entry></row>
 155
 156           <row><entry><varname>vrf</varname></entry>
 157           <entry>A Virtual Routing and Forwarding (<ulink url="https://www.kernel.org/doc/Documentation/networking/vrf.txt">VRF</ulink>) interface to create separate routing and forwarding domains.</entry></row>
 158
 159           <row><entry><varname>vcan</varname></entry>
 160           <entry>The virtual CAN driver (vcan). Similar to the network loopback devices, vcan offers a virtual local CAN interface.</entry></row>
 161
 162           <row><entry><varname>vxcan</varname></entry>
 163           <entry>The virtual CAN tunnel driver (vxcan). Similar to the virtual ethernet driver veth, vxcan implements a local CAN traffic tunnel between two virtual CAN network devices. When creating a vxcan, two vxcan devices are created as pair. When one end receives the packet it appears on its pair and vice versa. The vxcan can be used for cross namespace communication.
 164           </entry></row>
 165
 166           <row><entry><varname>wireguard</varname></entry>
 167           <entry>WireGuard Secure Network Tunnel.</entry></row>
 168
 169           <row><entry><varname>netdevsim</varname></entry>
 170           <entry> A simulator. This simulated networking device is used for testing various networking APIs and at this time is particularly focused on testing hardware offloading related interfaces.</entry></row>
 171
 172           <row><entry><varname>fou</varname></entry>
 173           <entry>Foo-over-UDP tunneling.</entry></row>
 174
 175         </tbody>
 176       </tgroup>
 177     </table>
 178
 179   </refsect1>
 180
 181   <refsect1>
 182     <title>[Match] Section Options</title>
 183
 184     <para>A virtual network device is only created if the
 185     <literal>[Match]</literal> section matches the current
 186     environment, or if the section is empty. The following keys are
 187     accepted:</para>
 188
 189     <variablelist class='network-directives'>
 190       <varlistentry>
 191         <term><varname>Host=</varname></term>
 192         <listitem>
 193           <para>Matches against the hostname or machine ID of the
 194           host. See <literal>ConditionHost=</literal> in
 195           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 196           for details.
 197           </para>
 198         </listitem>
 199       </varlistentry>
 200       <varlistentry>
 201         <term><varname>Virtualization=</varname></term>
 202         <listitem>
 203           <para>Checks whether the system is executed in a virtualized
 204           environment and optionally test whether it is a specific
 205           implementation. See
 206           <literal>ConditionVirtualization=</literal> in
 207           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 208           for details.
 209           </para>
 210         </listitem>
 211       </varlistentry>
 212       <varlistentry>
 213         <term><varname>KernelCommandLine=</varname></term>
 214         <listitem>
 215           <para>Checks whether a specific kernel command line option
 216           is set (or if prefixed with the exclamation mark unset). See
 217           <literal>ConditionKernelCommandLine=</literal> in
 218           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 219           for details.
 220           </para>
 221         </listitem>
 222       </varlistentry>
 223       <varlistentry>
 224         <term><varname>KernelVersion=</varname></term>
 225         <listitem>
 226           <para>Checks whether the kernel version (as reported by <command>uname -r</command>) matches a certain
 227           expression (or if prefixed with the exclamation mark does not match it). See
 228           <literal>ConditionKernelVersion=</literal> in
 229           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details.
 230           </para>
 231         </listitem>
 232       </varlistentry>
 233       <varlistentry>
 234         <term><varname>Architecture=</varname></term>
 235         <listitem>
 236           <para>Checks whether the system is running on a specific
 237           architecture. See <literal>ConditionArchitecture=</literal> in
 238           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 239           for details.
 240           </para>
 241         </listitem>
 242       </varlistentry>
 243     </variablelist>
 244
 245   </refsect1>
 246
 247   <refsect1>
 248     <title>[NetDev] Section Options</title>
 249
 250       <para>The <literal>[NetDev]</literal> section accepts the
 251       following keys:</para>
 252
 253       <variablelist class='network-directives'>
 254         <varlistentry>
 255           <term><varname>Description=</varname></term>
 256           <listitem>
 257             <para>A free-form description of the netdev.</para>
 258           </listitem>
 259         </varlistentry>
 260         <varlistentry>
 261           <term><varname>Name=</varname></term>
 262           <listitem>
 263             <para>The interface name used when creating the netdev.
 264             This option is compulsory.</para>
 265           </listitem>
 266         </varlistentry>
 267         <varlistentry>
 268           <term><varname>Kind=</varname></term>
 269           <listitem>
 270             <para>The netdev kind. This option is compulsory. See the
 271             <literal>Supported netdev kinds</literal> section for the
 272             valid keys.</para>
 273           </listitem>
 274         </varlistentry>
 275         <varlistentry>
 276           <term><varname>MTUBytes=</varname></term>
 277           <listitem>
 278             <para>The maximum transmission unit in bytes to set for the device. The usual suffixes K, M, G,
 279             are supported and are understood to the base of 1024. For <literal>tun</literal> or
 280             <literal>tap</literal> devices, <varname>MTUBytes=</varname> setting is not currently supported in
 281             <literal>[NetDev]</literal> section. Please specify it in <literal>[Link]</literal> section of
 282             corresponding
 283             <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 284             files.</para>
 285           </listitem>
 286         </varlistentry>
 287         <varlistentry>
 288           <term><varname>MACAddress=</varname></term>
 289           <listitem>
 290             <para>The MAC address to use for the device. If none is
 291             given, one is generated based on the interface name and
 292             the
 293             <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 294             For <literal>tun</literal> or <literal>tap</literal> devices, <varname>MACAddress=</varname> setting
 295             is not currently supported in <literal>[NetDev]</literal> section. Please specify it in
 296             <literal>[Link]</literal> section of corresponding
 297             <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 298             files.</para>
 299           </listitem>
 300         </varlistentry>
 301       </variablelist>
 302   </refsect1>
 303
 304     <refsect1>
 305     <title>[Bridge] Section Options</title>
 306
 307       <para>The <literal>[Bridge]</literal> section only applies for
 308       netdevs of kind <literal>bridge</literal>, and accepts the
 309       following keys:</para>
 310
 311       <variablelist class='network-directives'>
 312         <varlistentry>
 313           <term><varname>HelloTimeSec=</varname></term>
 314           <listitem>
 315             <para>HelloTimeSec specifies the number of seconds between two hello packets
 316             sent out by the root bridge and the designated bridges. Hello packets are
 317             used to communicate information about the topology throughout the entire
 318             bridged local area network.</para>
 319           </listitem>
 320         </varlistentry>
 321         <varlistentry>
 322           <term><varname>MaxAgeSec=</varname></term>
 323           <listitem>
 324             <para>MaxAgeSec specifies the number of seconds of maximum message age.
 325             If the last seen (received) hello packet is more than this number of
 326             seconds old, the bridge in question will start the takeover procedure
 327             in attempt to become the Root Bridge itself.</para>
 328           </listitem>
 329         </varlistentry>
 330         <varlistentry>
 331           <term><varname>ForwardDelaySec=</varname></term>
 332           <listitem>
 333             <para>ForwardDelaySec specifies the number of seconds spent in each
 334             of the Listening and Learning states before the Forwarding state is entered.</para>
 335           </listitem>
 336         </varlistentry>
 337         <varlistentry>
 338           <term><varname>AgeingTimeSec=</varname></term>
 339           <listitem>
 340             <para>This specifies the number of seconds a MAC Address will be kept in
 341             the forwarding database after having a packet received from this MAC Address.</para>
 342           </listitem>
 343         </varlistentry>
 344         <varlistentry>
 345           <term><varname>Priority=</varname></term>
 346           <listitem>
 347             <para>The priority of the bridge. An integer between 0 and 65535. A lower value
 348             means higher priority. The bridge having the lowest priority will be elected as root bridge.</para>
 349           </listitem>
 350         </varlistentry>
 351         <varlistentry>
 352           <term><varname>GroupForwardMask=</varname></term>
 353           <listitem>
 354             <para>A 16-bit bitmask represented as an integer which allows forwarding of link
 355             local frames with 802.1D reserved addresses (01:80:C2:00:00:0X). A logical AND
 356             is performed between the specified bitmask and the exponentiation of 2^X, the
 357             lower nibble of the last octet of the MAC address. For example, a value of 8
 358             would allow forwarding of frames addressed to 01:80:C2:00:00:03 (802.1X PAE).</para>
 359           </listitem>
 360         </varlistentry>
 361         <varlistentry>
 362           <term><varname>DefaultPVID=</varname></term>
 363           <listitem>
 364             <para>This specifies the default port VLAN ID of a newly attached bridge port.
 365             Set this to an integer in the range 1–4094 or <literal>none</literal> to disable the PVID.</para>
 366           </listitem>
 367         </varlistentry>
 368         <varlistentry>
 369           <term><varname>MulticastQuerier=</varname></term>
 370           <listitem>
 371             <para>Takes a boolean. This setting controls the IFLA_BR_MCAST_QUERIER option in the kernel.
 372             If enabled, the kernel will send general ICMP queries from a zero source address.
 373             This feature should allow faster convergence on startup, but it causes some
 374             multicast-aware switches to misbehave and disrupt forwarding of multicast packets.
 375             When unset, the kernel's default will be used.
 376             </para>
 377           </listitem>
 378         </varlistentry>
 379         <varlistentry>
 380           <term><varname>MulticastSnooping=</varname></term>
 381           <listitem>
 382             <para>Takes a boolean. This setting controls the IFLA_BR_MCAST_SNOOPING option in the kernel.
 383             If enabled, IGMP snooping monitors the Internet Group Management Protocol (IGMP) traffic
 384             between hosts and multicast routers. When unset, the kernel's default will be used.
 385             </para>
 386           </listitem>
 387         </varlistentry>
 388         <varlistentry>
 389           <term><varname>VLANFiltering=</varname></term>
 390           <listitem>
 391             <para>Takes a boolean. This setting controls the IFLA_BR_VLAN_FILTERING option in the kernel.
 392             If enabled, the bridge will be started in VLAN-filtering mode. When unset, the kernel's default will be used.
 393             </para>
 394           </listitem>
 395         </varlistentry>
 396           <varlistentry>
 397           <term><varname>STP=</varname></term>
 398           <listitem>
 399             <para>Takes a boolean. This enables the bridge's Spanning Tree Protocol (STP).
 400             When unset, the kernel's default will be used.
 401             </para>
 402           </listitem>
 403         </varlistentry>
 404       </variablelist>
 405   </refsect1>
 406
 407   <refsect1>
 408     <title>[VLAN] Section Options</title>
 409
 410       <para>The <literal>[VLAN]</literal> section only applies for
 411       netdevs of kind <literal>vlan</literal>, and accepts the
 412       following key:</para>
 413
 414       <variablelist class='network-directives'>
 415         <varlistentry>
 416           <term><varname>Id=</varname></term>
 417           <listitem>
 418             <para>The VLAN ID to use. An integer in the range 0–4094.
 419             This option is compulsory.</para>
 420           </listitem>
 421         </varlistentry>
 422         <varlistentry>
 423           <term><varname>GVRP=</varname></term>
 424           <listitem>
 425             <para>Takes a boolean. The Generic VLAN Registration Protocol (GVRP) is a protocol that
 426             allows automatic learning of VLANs on a network.
 427             When unset, the kernel's default will be used.
 428             </para>
 429           </listitem>
 430         </varlistentry>
 431         <varlistentry>
 432           <term><varname>MVRP=</varname></term>
 433           <listitem>
 434             <para>Takes a boolean. Multiple VLAN Registration Protocol (MVRP) formerly known as GARP VLAN
 435             Registration Protocol (GVRP) is a standards-based Layer 2 network protocol,
 436             for automatic configuration of VLAN information on switches. It was defined
 437             in the 802.1ak amendment to 802.1Q-2005. When unset, the kernel's default will be used.
 438             </para>
 439           </listitem>
 440         </varlistentry>
 441         <varlistentry>
 442           <term><varname>LooseBinding=</varname></term>
 443           <listitem>
 444             <para>Takes a boolean. The VLAN loose binding mode, in which only the operational state is passed
 445             from the parent to the associated VLANs, but the VLAN device state is not changed.
 446             When unset, the kernel's default will be used.</para>
 447           </listitem>
 448         </varlistentry>
 449         <varlistentry>
 450           <term><varname>ReorderHeader=</varname></term>
 451           <listitem>
 452             <para>Takes a boolean. The VLAN reorder header is set VLAN interfaces behave like physical interfaces.
 453             When unset, the kernel's default will be used.</para>
 454           </listitem>
 455         </varlistentry>
 456       </variablelist>
 457   </refsect1>
 458
 459   <refsect1>
 460     <title>[MACVLAN] Section Options</title>
 461
 462     <para>The <literal>[MACVLAN]</literal> section only applies for
 463     netdevs of kind <literal>macvlan</literal>, and accepts the
 464     following key:</para>
 465
 466     <variablelist class='network-directives'>
 467       <varlistentry>
 468         <term><varname>Mode=</varname></term>
 469         <listitem>
 470           <para>The MACVLAN mode to use. The supported options are
 471           <literal>private</literal>,
 472           <literal>vepa</literal>,
 473           <literal>bridge</literal>, and
 474           <literal>passthru</literal>.
 475           </para>
 476         </listitem>
 477       </varlistentry>
 478     </variablelist>
 479
 480   </refsect1>
 481
 482     <refsect1>
 483     <title>[MACVTAP] Section Options</title>
 484
 485     <para>The <literal>[MACVTAP]</literal> section applies for
 486     netdevs of kind <literal>macvtap</literal> and accepts the
 487     same key as <literal>[MACVLAN]</literal>.</para>
 488
 489     </refsect1>
 490
 491   <refsect1>
 492     <title>[IPVLAN] Section Options</title>
 493
 494     <para>The <literal>[IPVLAN]</literal> section only applies for
 495     netdevs of kind <literal>ipvlan</literal>, and accepts the
 496     following key:</para>
 497
 498     <variablelist class='network-directives'>
 499       <varlistentry>
 500         <term><varname>Mode=</varname></term>
 501           <listitem>
 502             <para>The IPVLAN mode to use. The supported options are
 503             <literal>L2</literal>,<literal>L3</literal> and <literal>L3S</literal>.
 504             </para>
 505           </listitem>
 506       </varlistentry>
 507        <varlistentry>
 508         <term><varname>Flags=</varname></term>
 509           <listitem>
 510             <para>The IPVLAN flags to use. The supported options are
 511             <literal>bridge</literal>,<literal>private</literal> and <literal>vepa</literal>.
 512             </para>
 513           </listitem>
 514       </varlistentry>
 515     </variablelist>
 516
 517   </refsect1>
 518
 519   <refsect1>
 520     <title>[VXLAN] Section Options</title>
 521     <para>The <literal>[VXLAN]</literal> section only applies for
 522     netdevs of kind <literal>vxlan</literal>, and accepts the
 523     following keys:</para>
 524
 525     <variablelist class='network-directives'>
 526       <varlistentry>
 527         <term><varname>Id=</varname></term>
 528         <listitem>
 529           <para>The VXLAN ID to use.</para>
 530         </listitem>
 531       </varlistentry>
 532       <varlistentry>
 533         <term><varname>Remote=</varname></term>
 534         <listitem>
 535           <para>Configures destination IP address.</para>
 536         </listitem>
 537       </varlistentry>
 538       <varlistentry>
 539         <term><varname>Local=</varname></term>
 540         <listitem>
 541           <para>Configures local IP address.</para>
 542         </listitem>
 543       </varlistentry>
 544         <varlistentry>
 545         <term><varname>TOS=</varname></term>
 546         <listitem>
 547           <para>The Type Of Service byte value for a vxlan interface.</para>
 548         </listitem>
 549       </varlistentry>
 550       <varlistentry>
 551         <term><varname>TTL=</varname></term>
 552         <listitem>
 553           <para>A fixed Time To Live N on Virtual eXtensible Local
 554           Area Network packets. N is a number in the range 1–255. 0
 555           is a special value meaning that packets inherit the TTL
 556           value.</para>
 557         </listitem>
 558       </varlistentry>
 559       <varlistentry>
 560         <term><varname>MacLearning=</varname></term>
 561         <listitem>
 562           <para>Takes a boolean. When true, enables dynamic MAC learning
 563           to discover remote MAC addresses.</para>
 564         </listitem>
 565       </varlistentry>
 566       <varlistentry>
 567         <term><varname>FDBAgeingSec=</varname></term>
 568         <listitem>
 569           <para>The lifetime of Forwarding Database entry learnt by
 570           the kernel, in seconds.</para>
 571         </listitem>
 572       </varlistentry>
 573       <varlistentry>
 574         <term><varname>MaximumFDBEntries=</varname></term>
 575         <listitem>
 576           <para>Configures maximum number of FDB entries.</para>
 577         </listitem>
 578       </varlistentry>
 579       <varlistentry>
 580         <term><varname>ReduceARPProxy=</varname></term>
 581         <listitem>
 582           <para>Takes a boolean. When true, bridge-connected VXLAN tunnel
 583           endpoint answers ARP requests from the local bridge on behalf
 584           of remote Distributed Overlay Virtual Ethernet
 585           <ulink url="https://en.wikipedia.org/wiki/Distributed_Overlay_Virtual_Ethernet">
 586           (DVOE)</ulink> clients. Defaults to false.</para>
 587         </listitem>
 588       </varlistentry>
 589       <varlistentry>
 590         <term><varname>L2MissNotification=</varname></term>
 591         <listitem>
 592           <para>Takes a boolean. When true, enables netlink LLADDR miss
 593           notifications.</para>
 594         </listitem>
 595       </varlistentry>
 596       <varlistentry>
 597         <term><varname>L3MissNotification=</varname></term>
 598         <listitem>
 599           <para>Takes a boolean. When true, enables netlink IP address miss
 600           notifications.</para>
 601         </listitem>
 602       </varlistentry>
 603       <varlistentry>
 604         <term><varname>RouteShortCircuit=</varname></term>
 605         <listitem>
 606           <para>Takes a boolean. When true, route short circuiting is turned
 607           on.</para>
 608         </listitem>
 609       </varlistentry>
 610       <varlistentry>
 611         <term><varname>UDPChecksum=</varname></term>
 612         <listitem>
 613           <para>Takes a boolean. When true, transmitting UDP checksums when doing VXLAN/IPv4 is turned on.</para>
 614         </listitem>
 615       </varlistentry>
 616       <varlistentry>
 617         <term><varname>UDP6ZeroChecksumTx=</varname></term>
 618         <listitem>
 619           <para>Takes a boolean. When true, sending zero checksums in VXLAN/IPv6 is turned on.</para>
 620         </listitem>
 621       </varlistentry>
 622       <varlistentry>
 623         <term><varname>UDP6ZeroChecksumRx=</varname></term>
 624         <listitem>
 625           <para>Takes a boolean. When true, receiving zero checksums in VXLAN/IPv6 is turned on.</para>
 626         </listitem>
 627       </varlistentry>
 628       <varlistentry>
 629         <term><varname>RemoteChecksumTx=</varname></term>
 630         <listitem>
 631           <para>Takes a boolean. When true, remote transmit checksum offload of VXLAN is turned on.</para>
 632         </listitem>
 633       </varlistentry>
 634       <varlistentry>
 635         <term><varname>RemoteChecksumRx=</varname></term>
 636         <listitem>
 637           <para>Takes a boolean. When true, remote receive checksum offload in VXLAN is turned on.</para>
 638         </listitem>
 639       </varlistentry>
 640     <varlistentry>
 641       <term><varname>GroupPolicyExtension=</varname></term>
 642       <listitem>
 643         <para>Takes a boolean. When true, it enables Group Policy VXLAN extension security label mechanism
 644         across network peers based on VXLAN. For details about the Group Policy VXLAN, see the
 645         <ulink url="https://tools.ietf.org/html/draft-smith-vxlan-group-policy">
 646         VXLAN Group Policy </ulink> document. Defaults to false.</para>
 647       </listitem>
 648     </varlistentry>
 649     <varlistentry>
 650       <term><varname>DestinationPort=</varname></term>
 651       <listitem>
 652         <para>Configures the default destination UDP port on a per-device basis.
 653         If destination port is not specified then Linux kernel default will be used.
 654         Set destination port 4789 to get the IANA assigned value. If not set or if the
 655         destination port is assigned the empty string the default port of 4789 is used.</para>
 656       </listitem>
 657     </varlistentry>
 658     <varlistentry>
 659       <term><varname>PortRange=</varname></term>
 660         <listitem>
 661           <para>Configures VXLAN port range. VXLAN bases source
 662           UDP port based on flow to help the receiver to be able
 663           to load balance based on outer header flow. It
 664           restricts the port range to the normal UDP local
 665           ports, and allows overriding via configuration.</para>
 666         </listitem>
 667       </varlistentry>
 668     <varlistentry>
 669       <term><varname>FlowLabel=</varname></term>
 670         <listitem>
 671           <para>Specifies the flow label to use in outgoing packets.
 672           The valid range is 0-1048575.
 673           </para>
 674         </listitem>
 675       </varlistentry>
 676     </variablelist>
 677   </refsect1>
 678   <refsect1>
 679     <title>[GENEVE] Section Options</title>
 680     <para>The <literal>[GENEVE]</literal> section only applies for
 681     netdevs of kind <literal>geneve</literal>, and accepts the
 682     following keys:</para>
 683
 684     <variablelist class='network-directives'>
 685       <varlistentry>
 686         <term><varname>Id=</varname></term>
 687         <listitem>
 688           <para>Specifies the Virtual Network Identifier (VNI) to use. Ranges [0-16777215].</para>
 689         </listitem>
 690       </varlistentry>
 691       <varlistentry>
 692         <term><varname>Remote=</varname></term>
 693         <listitem>
 694           <para>Specifies the unicast destination IP address to use in outgoing packets.</para>
 695         </listitem>
 696       </varlistentry>
 697       <varlistentry>
 698         <term><varname>TOS=</varname></term>
 699         <listitem>
 700           <para>Specifies the TOS value to use in outgoing packets. Ranges [1-255].</para>
 701         </listitem>
 702       </varlistentry>
 703       <varlistentry>
 704         <term><varname>TTL=</varname></term>
 705         <listitem>
 706           <para>Specifies the TTL value to use in outgoing packets. Ranges [1-255].</para>
 707         </listitem>
 708       </varlistentry>
 709       <varlistentry>
 710         <term><varname>UDPChecksum=</varname></term>
 711         <listitem>
 712           <para>Takes a boolean. When true, specifies if UDP checksum is calculated for transmitted packets over IPv4.</para>
 713         </listitem>
 714       </varlistentry>
 715       <varlistentry>
 716         <term><varname>UDP6ZeroChecksumTx=</varname></term>
 717         <listitem>
 718           <para>Takes a boolean. When true, skip UDP checksum calculation for transmitted packets over IPv6.</para>
 719         </listitem>
 720       </varlistentry>
 721       <varlistentry>
 722         <term><varname>UDP6ZeroChecksumRx=</varname></term>
 723         <listitem>
 724           <para>Takes a boolean. When true, allows incoming UDP packets over IPv6 with zero checksum field.</para>
 725         </listitem>
 726       </varlistentry>
 727     <varlistentry>
 728       <term><varname>DestinationPort=</varname></term>
 729       <listitem>
 730         <para>Specifies destination port. Defaults to 6081. If not set or assigned the empty string, the default
 731         port of 6081 is used.</para>
 732       </listitem>
 733     </varlistentry>
 734     <varlistentry>
 735       <term><varname>FlowLabel=</varname></term>
 736         <listitem>
 737           <para>Specifies the flow label to use in outgoing packets.</para>
 738         </listitem>
 739       </varlistentry>
 740     </variablelist>
 741   </refsect1>
 742   <refsect1>
 743     <title>[Tunnel] Section Options</title>
 744
 745     <para>The <literal>[Tunnel]</literal> section only applies for
 746     netdevs of kind
 747     <literal>ipip</literal>,
 748     <literal>sit</literal>,
 749     <literal>gre</literal>,
 750     <literal>gretap</literal>,
 751     <literal>ip6gre</literal>,
 752     <literal>ip6gretap</literal>,
 753     <literal>vti</literal>,
 754     <literal>vti6</literal>, and
 755     <literal>ip6tnl</literal> and accepts
 756     the following keys:</para>
 757
 758     <variablelist class='network-directives'>
 759       <varlistentry>
 760         <term><varname>Local=</varname></term>
 761         <listitem>
 762           <para>A static local address for tunneled packets. It must
 763           be an address on another interface of this host.</para>
 764         </listitem>
 765       </varlistentry>
 766       <varlistentry>
 767         <term><varname>Remote=</varname></term>
 768         <listitem>
 769           <para>The remote endpoint of the tunnel.</para>
 770         </listitem>
 771       </varlistentry>
 772       <varlistentry>
 773         <term><varname>TOS=</varname></term>
 774         <listitem>
 775           <para>The Type Of Service byte value for a tunnel interface.
 776           For details about the TOS, see the
 777           <ulink url="http://tools.ietf.org/html/rfc1349"> Type of
 778           Service in the Internet Protocol Suite </ulink> document.
 779           </para>
 780         </listitem>
 781       </varlistentry>
 782       <varlistentry>
 783         <term><varname>TTL=</varname></term>
 784         <listitem>
 785           <para>A fixed Time To Live N on tunneled packets. N is a
 786           number in the range 1–255. 0 is a special value meaning that
 787           packets inherit the TTL value. The default value for IPv4
 788           tunnels is: inherit. The default value for IPv6 tunnels is
 789           64.</para>
 790         </listitem>
 791       </varlistentry>
 792       <varlistentry>
 793         <term><varname>DiscoverPathMTU=</varname></term>
 794         <listitem>
 795           <para>Takes a boolean. When true, enables Path MTU Discovery on
 796           the tunnel.</para>
 797         </listitem>
 798       </varlistentry>
 799       <varlistentry>
 800         <term><varname>IPv6FlowLabel=</varname></term>
 801         <listitem>
 802           <para>Configures the 20-bit flow label (see <ulink url="https://tools.ietf.org/html/rfc6437">
 803           RFC 6437</ulink>) field in the IPv6 header (see <ulink url="https://tools.ietf.org/html/rfc2460">
 804           RFC 2460</ulink>), which is used by a node to label packets of a flow.
 805           It is only used for IPv6 tunnels.
 806           A flow label of zero is used to indicate packets that have
 807           not been labeled.
 808           It can be configured to a value in the range 0–0xFFFFF, or be
 809           set to <literal>inherit</literal>, in which case the original flowlabel is used.</para>
 810         </listitem>
 811       </varlistentry>
 812       <varlistentry>
 813         <term><varname>CopyDSCP=</varname></term>
 814         <listitem>
 815           <para>Takes a boolean. When true, the Differentiated Service Code
 816           Point (DSCP) field will be copied to the inner header from
 817           outer header during the decapsulation of an IPv6 tunnel
 818           packet. DSCP is a field in an IP packet that enables different
 819           levels of service to be assigned to network traffic.
 820           Defaults to <literal>no</literal>.
 821           </para>
 822         </listitem>
 823       </varlistentry>
 824       <varlistentry>
 825         <term><varname>EncapsulationLimit=</varname></term>
 826         <listitem>
 827           <para>The Tunnel Encapsulation Limit option specifies how many additional
 828           levels of encapsulation are permitted to be prepended to the packet.
 829           For example, a Tunnel Encapsulation Limit option containing a limit
 830           value of zero means that a packet carrying that option may not enter
 831           another tunnel before exiting the current tunnel.
 832           (see <ulink url="https://tools.ietf.org/html/rfc2473#section-4.1.1"> RFC 2473</ulink>).
 833           The valid range is 0–255 and <literal>none</literal>. Defaults to 4.
 834         </para>
 835         </listitem>
 836       </varlistentry>
 837       <varlistentry>
 838         <term><varname>Key=</varname></term>
 839         <listitem>
 840           <para>The <varname>Key=</varname> parameter specifies the same key to use in
 841           both directions (<varname>InputKey=</varname> and <varname>OutputKey=</varname>).
 842           The <varname>Key=</varname> is either a number or an IPv4 address-like dotted quad.
 843           It is used as mark-configured SAD/SPD entry as part of the lookup key (both in data
 844           and control path) in ip xfrm (framework used to implement IPsec protocol).
 845           See <ulink url="http://man7.org/linux/man-pages/man8/ip-xfrm.8.html">
 846           ip-xfrm — transform configuration</ulink> for details. It is only used for VTI/VTI6
 847           tunnels.</para>
 848         </listitem>
 849       </varlistentry>
 850       <varlistentry>
 851         <term><varname>InputKey=</varname></term>
 852         <listitem>
 853           <para>The <varname>InputKey=</varname> parameter specifies the key to use for input.
 854           The format is same as <varname>Key=</varname>. It is only used for VTI/VTI6 tunnels.</para>
 855         </listitem>
 856       </varlistentry>
 857       <varlistentry>
 858         <term><varname>OutputKey=</varname></term>
 859         <listitem>
 860           <para>The <varname>OutputKey=</varname> parameter specifies the key to use for output.
 861           The format is same as <varname>Key=</varname>. It is only used for VTI/VTI6 tunnels.</para>
 862         </listitem>
 863       </varlistentry>
 864       <varlistentry>
 865         <term><varname>Mode=</varname></term>
 866         <listitem>
 867           <para>An <literal>ip6tnl</literal> tunnel can be in one of three
 868           modes
 869           <literal>ip6ip6</literal> for IPv6 over IPv6,
 870           <literal>ipip6</literal> for IPv4 over IPv6 or
 871           <literal>any</literal> for either.
 872           </para>
 873         </listitem>
 874       </varlistentry>
 875       <varlistentry>
 876         <term><varname>Independent=</varname></term>
 877         <listitem>
 878           <para>Takes a boolean. When true tunnel does not require .network file. Created as "tunnel@NONE".
 879           Defaults to <literal>false</literal>.
 880           </para>
 881         </listitem>
 882       </varlistentry>
 883       <varlistentry>
 884         <term><varname>AllowLocalRemote=</varname></term>
 885         <listitem>
 886           <para>Takes a boolean. When true allows tunnel traffic on <varname>ip6tnl</varname> devices where the remote endpoint is a local host address.
 887           When unset, the kernel's default will be used.
 888           </para>
 889         </listitem>
 890       </varlistentry>
 891       <varlistentry>
 892         <term><varname>FooOverUDP=</varname></term>
 893         <listitem>
 894           <para>Takes a boolean. Specifies whether <varname>FooOverUDP=</varname> tunnel is to be configured.
 895           Defaults to false. For more detail information see
 896           <ulink url="https://lwn.net/Articles/614348">Foo over UDP</ulink></para>
 897         </listitem>
 898       </varlistentry>
 899       <varlistentry>
 900         <term><varname>FOUDestinationPort=</varname></term>
 901         <listitem>
 902           <para>The <varname>FOUDestinationPort=</varname> specifies the UDP destination port for encapsulation.
 903           This field is mandatory and is not set by default.</para>
 904         </listitem>
 905       </varlistentry>
 906       <varlistentry>
 907         <term><varname>FOUSourcePort=</varname></term>
 908         <listitem>
 909           <para>The <constant>FOUSourcePort=</constant> specifies the UDP source port for encapsulation. Defaults to <varname>0</varname>,
 910           that is, the source port for packets is left to the network stack to decide.</para>
 911         </listitem>
 912       </varlistentry>
 913       <varlistentry>
 914         <term><varname>Encapsulation=</varname></term>
 915         <listitem>
 916           <para>Accepts the same key as <literal>[FooOverUDP]</literal></para>
 917         </listitem>
 918       </varlistentry>
 919       <varlistentry>
 920         <term><varname>IPv6RapidDeploymentPrefix=</varname></term>
 921         <listitem>
 922           <para>Reconfigure the tunnel for <ulink url="https://tools.ietf.org/html/rfc5569">IPv6 Rapid
 923           Deployment</ulink>, also known as 6rd. The value is an ISP-specific IPv6 prefix with a non-zero length. Only
 924           applicable to SIT tunnels.</para>
 925         </listitem>
 926       </varlistentry>
 927       <varlistentry>
 928         <term><varname>SerializeTunneledPackets=</varname></term>
 929         <listitem>
 930           <para>Takes a boolean. If set to yes, then packets are serialized. Only applies for ERSPAN tunnel.
 931           When unset, the kernel's default will be used.
 932           </para>
 933         </listitem>
 934       </varlistentry>
 935       <varlistentry>
 936         <term><varname>ERSPANIndex=</varname></term>
 937         <listitem>
 938           <para>Specifies the ERSPAN index field for the interface, an integer in the range 1-1048575 associated with
 939           the ERSPAN traffic's source port and direction. This field is mandatory.
 940           </para>
 941         </listitem>
 942       </varlistentry>
 943     </variablelist>
 944   </refsect1>
 945
 946   <refsect1>
 947     <title>[FooOverUDP] Section Options</title>
 948
 949     <para>The <literal>[FooOverUDP]</literal> section only applies for
 950     netdevs of kind <literal>fou</literal> and accepts the
 951     following keys:</para>
 952
 953     <variablelist class='network-directives'>
 954       <varlistentry>
 955         <term><varname>Protocol=</varname></term>
 956         <listitem>
 957           <para>The <varname>Protocol=</varname> specifies the protocol number of the
 958           packets arriving at the UDP port. This field is mandatory and is not set by default. Valid range is 1-255.</para>
 959         </listitem>
 960       </varlistentry>
 961       <varlistentry>
 962         <term><varname>Encapsulation=</varname></term>
 963         <listitem>
 964           <para>Specifies the encapsulation mechanism used to store networking packets of various protocols inside the UDP packets. Supports the following values:
 965
 966           <literal>FooOverUDP</literal> provides the simplest no frills model of UDP encapsulation, it simply encapsulates
 967           packets directly in the UDP payload.
 968           <literal>GenericUDPEncapsulation</literal> is a generic and extensible encapsulation, it allows encapsulation of packets for any IP
 969           protocol and optional data as part of the encapsulation.
 970           For more detailed information see <ulink url="https://lwn.net/Articles/615044">Generic UDP Encapsulation</ulink>.
 971           Defaults to <literal>FooOverUDP</literal>.
 972           </para>
 973         </listitem>
 974       </varlistentry>
 975       <varlistentry>
 976         <term><varname>Port=</varname></term>
 977         <listitem>
 978           <para>Specifies the port number, where the IP encapsulation packets will arrive. Please take note that the packets
 979           will arrive with the encapsulation will be removed. Then they will be manually fed back into the network stack, and sent ahead
 980           for delivery to the real destination. This option is mandatory.</para>
 981         </listitem>
 982         </varlistentry>
 983       </variablelist>
 984   </refsect1>
 985   <refsect1>
 986     <title>[Peer] Section Options</title>
 987
 988       <para>The <literal>[Peer]</literal> section only applies for
 989       netdevs of kind <literal>veth</literal> and accepts the
 990       following keys:</para>
 991
 992       <variablelist class='network-directives'>
 993         <varlistentry>
 994           <term><varname>Name=</varname></term>
 995           <listitem>
 996             <para>The interface name used when creating the netdev.
 997             This option is compulsory.</para>
 998           </listitem>
 999         </varlistentry>
1000         <varlistentry>
1001           <term><varname>MACAddress=</varname></term>
1002           <listitem>
1003             <para>The peer MACAddress, if not set, it is generated in
1004             the same way as the MAC address of the main
1005             interface.</para>
1006           </listitem>
1007         </varlistentry>
1008       </variablelist>
1009   </refsect1>
1010   <refsect1>
1011   <title>[VXCAN] Section Options</title>
1012       <para>The <literal>[VXCAN]</literal> section only applies for
1013       netdevs of kind <literal>vxcan</literal> and accepts the
1014       following key:</para>
1015
1016       <variablelist class='network-directives'>
1017         <varlistentry>
1018           <term><varname>Peer=</varname></term>
1019           <listitem>
1020             <para>The peer interface name used when creating the netdev.
1021             This option is compulsory.</para>
1022           </listitem>
1023         </varlistentry>
1024       </variablelist>
1025   </refsect1>
1026   <refsect1>
1027     <title>[Tun] Section Options</title>
1028
1029     <para>The <literal>[Tun]</literal> section only applies for
1030     netdevs of kind <literal>tun</literal>, and accepts the following
1031     keys:</para>
1032
1033     <variablelist class='network-directives'>
1034       <varlistentry>
1035         <term><varname>OneQueue=</varname></term>
1036         <listitem><para>Takes a boolean. Configures whether
1037         all packets are queued at the device (enabled), or a fixed
1038         number of packets are queued at the device and the rest at the
1039         <literal>qdisc</literal>. Defaults to
1040         <literal>no</literal>.</para>
1041         </listitem>
1042       </varlistentry>
1043       <varlistentry>
1044         <term><varname>MultiQueue=</varname></term>
1045         <listitem><para>Takes a boolean. Configures whether
1046         to use multiple file descriptors (queues) to parallelize
1047         packets sending and receiving. Defaults to
1048         <literal>no</literal>.</para>
1049         </listitem>
1050       </varlistentry>
1051       <varlistentry>
1052         <term><varname>PacketInfo=</varname></term>
1053         <listitem><para>Takes a boolean. Configures whether
1054         packets should be prepended with four extra bytes (two flag
1055         bytes and two protocol bytes). If disabled, it indicates that
1056         the packets will be pure IP packets. Defaults to
1057         <literal>no</literal>.</para>
1058         </listitem>
1059       </varlistentry>
1060       <varlistentry>
1061         <term><varname>VNetHeader=</varname></term>
1062         <listitem><para>Takes a boolean. Configures
1063         IFF_VNET_HDR flag for a tap device. It allows sending
1064         and receiving larger Generic Segmentation Offload (GSO)
1065         packets. This may increase throughput significantly.
1066         Defaults to
1067         <literal>no</literal>.</para>
1068         </listitem>
1069       </varlistentry>
1070       <varlistentry>
1071         <term><varname>User=</varname></term>
1072         <listitem><para>User to grant access to the
1073         <filename>/dev/net/tun</filename> device.</para>
1074         </listitem>
1075       </varlistentry>
1076       <varlistentry>
1077         <term><varname>Group=</varname></term>
1078         <listitem><para>Group to grant access to the
1079         <filename>/dev/net/tun</filename> device.</para>
1080         </listitem>
1081       </varlistentry>
1082
1083     </variablelist>
1084
1085   </refsect1>
1086
1087   <refsect1>
1088     <title>[Tap] Section Options</title>
1089
1090     <para>The <literal>[Tap]</literal> section only applies for
1091     netdevs of kind <literal>tap</literal>, and accepts the same keys
1092     as the <literal>[Tun]</literal> section.</para>
1093   </refsect1>
1094
1095   <refsect1>
1096     <title>[WireGuard] Section Options</title>
1097
1098     <para>The <literal>[WireGuard]</literal> section accepts the following
1099     keys:</para>
1100
1101     <variablelist class='network-directives'>
1102       <varlistentry>
1103         <term><varname>PrivateKey=</varname></term>
1104         <listitem>
1105           <para>The Base64 encoded private key for the interface. It can be
1106             generated using the <command>wg genkey</command> command
1107             (see <citerefentry project="wireguard"><refentrytitle>wg</refentrytitle><manvolnum>8</manvolnum></citerefentry>).
1108             This option is mandatory to use WireGuard.
1109             Note that because this information is secret, you may want to set
1110             the permissions of the .netdev file to be owned by <literal>root:systemd-network</literal>
1111             with a <literal>0640</literal> file mode.</para>
1112         </listitem>
1113       </varlistentry>
1114       <varlistentry>
1115         <term><varname>ListenPort=</varname></term>
1116         <listitem>
1117           <para>Sets UDP port for listening. Takes either value between 1 and 65535
1118             or <literal>auto</literal>. If <literal>auto</literal> is specified,
1119             the port is automatically generated based on interface name.
1120             Defaults to <literal>auto</literal>.</para>
1121         </listitem>
1122       </varlistentry>
1123       <varlistentry>
1124         <term><varname>FwMark=</varname></term>
1125         <listitem>
1126           <para>Sets a firewall mark on outgoing WireGuard packets from this interface.</para>
1127         </listitem>
1128       </varlistentry>
1129     </variablelist>
1130   </refsect1>
1131
1132   <refsect1>
1133     <title>[WireGuardPeer] Section Options</title>
1134
1135     <para>The <literal>[WireGuardPeer]</literal> section accepts the following
1136     keys:</para>
1137
1138     <variablelist class='network-directives'>
1139       <varlistentry>
1140         <term><varname>PublicKey=</varname></term>
1141         <listitem>
1142           <para>Sets a Base64 encoded public key calculated by <command>wg pubkey</command>
1143             (see <citerefentry project="wireguard"><refentrytitle>wg</refentrytitle><manvolnum>8</manvolnum></citerefentry>)
1144             from a private key, and usually transmitted out of band to the
1145             author of the configuration file. This option is mandatory for this
1146             section.</para>
1147         </listitem>
1148       </varlistentry>
1149       <varlistentry>
1150         <term><varname>PresharedKey=</varname></term>
1151         <listitem>
1152           <para>Optional preshared key for the interface. It can be generated
1153             by the <command>wg genpsk</command> command. This option adds an
1154             additional layer of symmetric-key cryptography to be mixed into the
1155             already existing public-key cryptography, for post-quantum
1156             resistance.
1157             Note that because this information is secret, you may want to set
1158             the permissions of the .netdev file to be owned by <literal>root:systemd-networkd</literal>
1159             with a <literal>0640</literal> file mode.</para>
1160         </listitem>
1161       </varlistentry>
1162       <varlistentry>
1163         <term><varname>AllowedIPs=</varname></term>
1164         <listitem>
1165           <para>Sets a comma-separated list of IP (v4 or v6) addresses with CIDR masks
1166             from which this peer is allowed to send incoming traffic and to
1167             which outgoing traffic for this peer is directed. The catch-all
1168             0.0.0.0/0 may be specified for matching all IPv4 addresses, and
1169             ::/0 may be specified for matching all IPv6 addresses. </para>
1170         </listitem>
1171       </varlistentry>
1172       <varlistentry>
1173         <term><varname>Endpoint=</varname></term>
1174         <listitem>
1175           <para>Sets an endpoint IP address or hostname, followed by a colon, and then
1176             a port number. This endpoint will be updated automatically once to
1177             the most recent source IP address and port of correctly
1178             authenticated packets from the peer at configuration time.</para>
1179         </listitem>
1180       </varlistentry>
1181       <varlistentry>
1182         <term><varname>PersistentKeepalive=</varname></term>
1183         <listitem>
1184           <para>Sets a seconds interval, between 1 and 65535 inclusive, of how often
1185             to send an authenticated empty packet to the peer for the purpose
1186             of keeping a stateful firewall or NAT mapping valid persistently.
1187             For example, if the interface very rarely sends traffic, but it
1188             might at anytime receive traffic from a peer, and it is behind NAT,
1189             the interface might benefit from having a persistent keepalive
1190             interval of 25 seconds. If set to 0 or "off", this option is
1191             disabled. By default or when unspecified, this option is off.
1192             Most users will not need this.</para>
1193         </listitem>
1194       </varlistentry>
1195     </variablelist>
1196   </refsect1>
1197
1198   <refsect1>
1199     <title>[Bond] Section Options</title>
1200
1201     <para>The <literal>[Bond]</literal> section accepts the following
1202     key:</para>
1203
1204     <variablelist class='network-directives'>
1205       <varlistentry>
1206         <term><varname>Mode=</varname></term>
1207         <listitem>
1208           <para>Specifies one of the bonding policies. The default is
1209           <literal>balance-rr</literal> (round robin). Possible values are
1210           <literal>balance-rr</literal>,
1211           <literal>active-backup</literal>,
1212           <literal>balance-xor</literal>,
1213           <literal>broadcast</literal>,
1214           <literal>802.3ad</literal>,
1215           <literal>balance-tlb</literal>, and
1216           <literal>balance-alb</literal>.
1217           </para>
1218         </listitem>
1219       </varlistentry>
1220
1221       <varlistentry>
1222         <term><varname>TransmitHashPolicy=</varname></term>
1223         <listitem>
1224           <para>Selects the transmit hash policy to use for slave
1225           selection in balance-xor, 802.3ad, and tlb modes. Possible
1226           values are
1227           <literal>layer2</literal>,
1228           <literal>layer3+4</literal>,
1229           <literal>layer2+3</literal>,
1230           <literal>encap2+3</literal>, and
1231           <literal>encap3+4</literal>.
1232           </para>
1233         </listitem>
1234       </varlistentry>
1235
1236       <varlistentry>
1237         <term><varname>LACPTransmitRate=</varname></term>
1238         <listitem>
1239           <para>Specifies the rate with which link partner transmits
1240           Link Aggregation Control Protocol Data Unit packets in
1241           802.3ad mode. Possible values are <literal>slow</literal>,
1242           which requests partner to transmit LACPDUs every 30 seconds,
1243           and <literal>fast</literal>, which requests partner to
1244           transmit LACPDUs every second. The default value is
1245           <literal>slow</literal>.</para>
1246         </listitem>
1247       </varlistentry>
1248
1249       <varlistentry>
1250         <term><varname>MIIMonitorSec=</varname></term>
1251         <listitem>
1252           <para>Specifies the frequency that Media Independent
1253           Interface link monitoring will occur. A value of zero
1254           disables MII link monitoring. This value is rounded down to
1255           the nearest millisecond. The default value is 0.</para>
1256         </listitem>
1257       </varlistentry>
1258
1259       <varlistentry>
1260         <term><varname>UpDelaySec=</varname></term>
1261         <listitem>
1262           <para>Specifies the delay before a link is enabled after a
1263           link up status has been detected. This value is rounded down
1264           to a multiple of MIIMonitorSec. The default value is
1265           0.</para>
1266         </listitem>
1267       </varlistentry>
1268
1269       <varlistentry>
1270         <term><varname>DownDelaySec=</varname></term>
1271         <listitem>
1272           <para>Specifies the delay before a link is disabled after a
1273           link down status has been detected. This value is rounded
1274           down to a multiple of MIIMonitorSec. The default value is
1275           0.</para>
1276         </listitem>
1277       </varlistentry>
1278
1279       <varlistentry>
1280         <term><varname>LearnPacketIntervalSec=</varname></term>
1281         <listitem>
1282           <para>Specifies the number of seconds between instances where the bonding
1283           driver sends learning packets to each slave peer switch.
1284           The valid range is 1–0x7fffffff; the default value is 1. This option
1285           has an effect only for the balance-tlb and balance-alb modes.</para>
1286         </listitem>
1287       </varlistentry>
1288
1289       <varlistentry>
1290         <term><varname>AdSelect=</varname></term>
1291         <listitem>
1292           <para>Specifies the 802.3ad aggregation selection logic to use. Possible values are
1293           <literal>stable</literal>,
1294           <literal>bandwidth</literal> and
1295           <literal>count</literal>.
1296           </para>
1297         </listitem>
1298       </varlistentry>
1299
1300       <varlistentry>
1301         <term><varname>AdActorSystemPriority=</varname></term>
1302         <listitem>
1303           <para>Specifies the 802.3ad actor system priority. Ranges [1-65535].</para>
1304         </listitem>
1305       </varlistentry>
1306
1307       <varlistentry>
1308         <term><varname>AdUserPortKey=</varname></term>
1309         <listitem>
1310           <para>Specifies the 802.3ad user defined portion of the port key. Ranges [0-1023].</para>
1311         </listitem>
1312       </varlistentry>
1313
1314       <varlistentry>
1315         <term><varname>AdActorSystem=</varname></term>
1316         <listitem>
1317           <para>Specifies the 802.3ad system mac address. This can not be either NULL or Multicast.</para>
1318         </listitem>
1319       </varlistentry>
1320
1321       <varlistentry>
1322         <term><varname>FailOverMACPolicy=</varname></term>
1323         <listitem>
1324           <para>Specifies whether the active-backup mode should set all slaves to
1325           the same MAC address at the time of enslavement or, when enabled, to perform special handling of the
1326           bond's MAC address in accordance with the selected policy. The default policy is none.
1327           Possible values are
1328           <literal>none</literal>,
1329           <literal>active</literal> and
1330           <literal>follow</literal>.
1331           </para>
1332         </listitem>
1333       </varlistentry>
1334
1335       <varlistentry>
1336         <term><varname>ARPValidate=</varname></term>
1337         <listitem>
1338           <para>Specifies whether or not ARP probes and replies should be
1339           validated in any mode that supports ARP monitoring, or whether
1340           non-ARP traffic should be filtered (disregarded) for link
1341           monitoring purposes. Possible values are
1342           <literal>none</literal>,
1343           <literal>active</literal>,
1344           <literal>backup</literal> and
1345           <literal>all</literal>.
1346           </para>
1347         </listitem>
1348       </varlistentry>
1349
1350       <varlistentry>
1351         <term><varname>ARPIntervalSec=</varname></term>
1352         <listitem>
1353           <para>Specifies the ARP link monitoring frequency in milliseconds.
1354           A value of 0 disables ARP monitoring. The default value is 0.
1355           </para>
1356         </listitem>
1357       </varlistentry>
1358
1359       <varlistentry>
1360         <term><varname>ARPIPTargets=</varname></term>
1361         <listitem>
1362           <para>Specifies the IP addresses to use as ARP monitoring peers when
1363           ARPIntervalSec is greater than 0. These are the targets of the ARP request
1364           sent to determine the health of the link to the targets.
1365           Specify these values in IPv4 dotted decimal format. At least one IP
1366           address must be given for ARP monitoring to function. The
1367           maximum number of targets that can be specified is 16. The
1368           default value is no IP addresses.
1369           </para>
1370         </listitem>
1371       </varlistentry>
1372
1373       <varlistentry>
1374         <term><varname>ARPAllTargets=</varname></term>
1375         <listitem>
1376           <para>Specifies the quantity of ARPIPTargets that must be reachable
1377           in order for the ARP monitor to consider a slave as being up.
1378           This option affects only active-backup mode for slaves with
1379           ARPValidate enabled. Possible values are
1380           <literal>any</literal> and
1381           <literal>all</literal>.
1382           </para>
1383         </listitem>
1384       </varlistentry>
1385
1386       <varlistentry>
1387         <term><varname>PrimaryReselectPolicy=</varname></term>
1388         <listitem>
1389           <para>Specifies the reselection policy for the primary slave.  This
1390           affects how the primary slave is chosen to become the active slave
1391           when failure of the active slave or recovery of the primary slave
1392           occurs. This option is designed to prevent flip-flopping between
1393           the primary slave and other slaves.  Possible values are
1394           <literal>always</literal>,
1395           <literal>better</literal> and
1396           <literal>failure</literal>.
1397           </para>
1398         </listitem>
1399       </varlistentry>
1400
1401       <varlistentry>
1402         <term><varname>ResendIGMP=</varname></term>
1403         <listitem>
1404           <para>Specifies the number of IGMP membership reports to be issued after
1405           a failover event. One membership report is issued immediately after
1406           the failover, subsequent packets are sent in each 200ms interval.
1407           The valid range is 0–255. Defaults to 1. A value of 0
1408           prevents the IGMP membership report from being issued in response
1409           to the failover event.
1410           </para>
1411         </listitem>
1412       </varlistentry>
1413
1414       <varlistentry>
1415         <term><varname>PacketsPerSlave=</varname></term>
1416         <listitem>
1417           <para>Specify the number of packets to transmit through a slave before
1418             moving to the next one. When set to 0, then a slave is chosen at
1419             random. The valid range is 0–65535. Defaults to 1. This option
1420             only has effect when in balance-rr mode.
1421           </para>
1422         </listitem>
1423       </varlistentry>
1424
1425       <varlistentry>
1426         <term><varname>GratuitousARP=</varname></term>
1427         <listitem>
1428           <para>Specify the number of peer notifications (gratuitous ARPs and
1429             unsolicited IPv6 Neighbor Advertisements) to be issued after a
1430             failover event.  As soon as the link is up on the new slave,
1431             a peer notification is sent on the  bonding device and each
1432             VLAN sub-device.  This is repeated at each link monitor interval
1433             (ARPIntervalSec or MIIMonitorSec, whichever is active) if the number is
1434             greater than 1. The valid range is 0–255. The default value is 1.
1435             These options affect only the active-backup mode.
1436           </para>
1437         </listitem>
1438       </varlistentry>
1439
1440       <varlistentry>
1441         <term><varname>AllSlavesActive=</varname></term>
1442         <listitem>
1443           <para>Takes a boolean. Specifies that duplicate frames (received on inactive ports)
1444           should be dropped when false, or delivered when true. Normally, bonding will drop
1445           duplicate frames (received on inactive ports), which is desirable for
1446           most users. But there are some times it is nice to allow duplicate
1447           frames to be delivered. The default value is false (drop duplicate frames
1448           received on inactive ports).
1449           </para>
1450         </listitem>
1451       </varlistentry>
1452
1453       <varlistentry>
1454         <term><varname>MinLinks=</varname></term>
1455         <listitem>
1456           <para>Specifies the minimum number of links that must be active before
1457           asserting carrier. The default value is 0.
1458           </para>
1459         </listitem>
1460       </varlistentry>
1461     </variablelist>
1462
1463     <para>For more detail information see
1464     <ulink url="https://www.kernel.org/doc/Documentation/networking/bonding.txt">
1465     Linux Ethernet Bonding Driver HOWTO</ulink></para>
1466
1467   </refsect1>
1468
1469   <refsect1>
1470     <title>Examples</title>
1471     <example>
1472       <title>/etc/systemd/network/25-bridge.netdev</title>
1473
1474       <programlisting>[NetDev]
1475 Name=bridge0
1476 Kind=bridge</programlisting>
1477     </example>
1478
1479     <example>
1480       <title>/etc/systemd/network/25-vlan1.netdev</title>
1481
1482       <programlisting>[Match]
1483 Virtualization=no
1484
1485 [NetDev]
1486 Name=vlan1
1487 Kind=vlan
1488
1489 [VLAN]
1490 Id=1</programlisting>
1491     </example>
1492     <example>
1493       <title>/etc/systemd/network/25-ipip.netdev</title>
1494       <programlisting>[NetDev]
1495 Name=ipip-tun
1496 Kind=ipip
1497 MTUBytes=1480
1498
1499 [Tunnel]
1500 Local=192.168.223.238
1501 Remote=192.169.224.239
1502 TTL=64</programlisting>
1503     </example>
1504     <example>
1505       <title>/etc/systemd/network/1-fou-tunnel.netdev</title>
1506       <programlisting>[NetDev]
1507 Name=fou-tun
1508 Kind=fou
1509
1510 [FooOverUDP]
1511 Port=5555
1512 Protocol=4
1513       </programlisting>
1514     </example>
1515     <example>
1516       <title>/etc/systemd/network/25-fou-ipip.netdev</title>
1517       <programlisting>[NetDev]
1518 Name=ipip-tun
1519 Kind=ipip
1520
1521 [Tunnel]
1522 Independent=yes
1523 Local=10.65.208.212
1524 Remote=10.65.208.211
1525 FooOverUDP=yes
1526 FOUDestinationPort=5555
1527       </programlisting>
1528     </example>
1529     <example>
1530       <title>/etc/systemd/network/25-tap.netdev</title>
1531       <programlisting>[NetDev]
1532 Name=tap-test
1533 Kind=tap
1534
1535 [Tap]
1536 MultiQueue=yes
1537 PacketInfo=yes</programlisting> </example>
1538
1539     <example>
1540       <title>/etc/systemd/network/25-sit.netdev</title>
1541       <programlisting>[NetDev]
1542 Name=sit-tun
1543 Kind=sit
1544 MTUBytes=1480
1545
1546 [Tunnel]
1547 Local=10.65.223.238
1548 Remote=10.65.223.239</programlisting>
1549     </example>
1550
1551     <example>
1552       <title>/etc/systemd/network/25-6rd.netdev</title>
1553       <programlisting>[NetDev]
1554 Name=6rd-tun
1555 Kind=sit
1556 MTUBytes=1480
1557
1558 [Tunnel]
1559 Local=10.65.223.238
1560 IPv6RapidDeploymentPrefix=2602::/24</programlisting>
1561     </example>
1562
1563     <example>
1564       <title>/etc/systemd/network/25-gre.netdev</title>
1565       <programlisting>[NetDev]
1566 Name=gre-tun
1567 Kind=gre
1568 MTUBytes=1480
1569
1570 [Tunnel]
1571 Local=10.65.223.238
1572 Remote=10.65.223.239</programlisting>
1573     </example>
1574
1575     <example>
1576       <title>/etc/systemd/network/25-vti.netdev</title>
1577
1578       <programlisting>[NetDev]
1579 Name=vti-tun
1580 Kind=vti
1581 MTUBytes=1480
1582
1583 [Tunnel]
1584 Local=10.65.223.238
1585 Remote=10.65.223.239</programlisting>
1586     </example>
1587
1588     <example>
1589       <title>/etc/systemd/network/25-veth.netdev</title>
1590       <programlisting>[NetDev]
1591 Name=veth-test
1592 Kind=veth
1593
1594 [Peer]
1595 Name=veth-peer</programlisting>
1596     </example>
1597
1598     <example>
1599       <title>/etc/systemd/network/25-bond.netdev</title>
1600       <programlisting>[NetDev]
1601 Name=bond1
1602 Kind=bond
1603
1604 [Bond]
1605 Mode=802.3ad
1606 TransmitHashPolicy=layer3+4
1607 MIIMonitorSec=1s
1608 LACPTransmitRate=fast
1609 </programlisting>
1610     </example>
1611
1612     <example>
1613       <title>/etc/systemd/network/25-dummy.netdev</title>
1614       <programlisting>[NetDev]
1615 Name=dummy-test
1616 Kind=dummy
1617 MACAddress=12:34:56:78:9a:bc</programlisting>
1618     </example>
1619     <example>
1620       <title>/etc/systemd/network/25-vrf.netdev</title>
1621       <para>Create a VRF interface with table 42.</para>
1622       <programlisting>[NetDev]
1623 Name=vrf-test
1624 Kind=vrf
1625
1626 [VRF]
1627 Table=42</programlisting>
1628     </example>
1629
1630     <example>
1631       <title>/etc/systemd/network/25-macvtap.netdev</title>
1632       <para>Create a MacVTap device.</para>
1633       <programlisting>[NetDev]
1634 Name=macvtap-test
1635 Kind=macvtap
1636       </programlisting>
1637     </example>
1638     <example>
1639       <title>/etc/systemd/network/25-wireguard.netdev</title>
1640       <programlisting>[NetDev]
1641 Name=wg0
1642 Kind=wireguard
1643
1644 [WireGuard]
1645 PrivateKey=EEGlnEPYJV//kbvvIqxKkQwOiS+UENyPncC4bF46ong=
1646 ListenPort=51820
1647
1648 [WireGuardPeer]
1649 PublicKey=RDf+LSpeEre7YEIKaxg+wbpsNV7du+ktR99uBEtIiCA=
1650 AllowedIPs=fd31:bf08:57cb::/48,192.168.26.0/24
1651 Endpoint=wireguard.example.com:51820</programlisting>
1652     </example>
1653   </refsect1>
1654   <refsect1>
1655     <title>See Also</title>
1656     <para>
1657       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1658       <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
1659       <citerefentry><refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1660       <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1661     </para>
1662   </refsect1>
1663
1664 </refentry>